General
Golf carts are primarily used for the transportation of golfers for use on golf courses, between golf courses and clubhouses, etc. However, their use has been expanded to serve as general purpose vehicles in retirement communities usually, but not always, associated with a golf course. Their use has continued to expand to where they are now street legal on roads having maximum speed limits of 35 mph, for example, and the vehicles themselves have a maximum speed of typically about 25 mph. As such, golf carts can now be seen in major cities such as New York City. Similar vehicles, referred to commonly as all-terrain vehicles (ATVs), are frequently used on back roads and trails. According to an entry from Wikipedia, an all-terrain vehicle (ATV), also known as a quad, quad bike, three-wheeler, or four-wheeler, is defined by the American National Standards Institute (ANSI) as a vehicle that travels on low-pressure tires, with a seat that is straddled by the operator, along with handlebars for steering control. It is designed to handle a wider variety of terrain than most other vehicles. An all-terrain vehicle is not, for the purposes herein, defined as a vehicle capable of travelling on all terrains, but rather by the Wikipedia definition or another similar definition.
Little attention has been paid to the safety of operators and passengers of such vehicles and many people have been injured and fatalities have occurred arising from the use of such vehicles.
Due to their low speed, such vehicles are exempt from federal motor vehicle safety standards that are applied to automobiles. However, due to the proliferation of such vehicles, there is now interest in providing safety restraint systems to protect passengers of these vehicles from injury and death as a result of accidents involving the vehicles. This problem is receiving increased attention due to the desire of the manufacturers of such vehicles to expand their use to higher speeds and on higher speed limit roads.
Occupant Protection Problem
Golf carts and similar all-terrain vehicles have little structure to absorb crash energy from frontal or side impacts. There is also little structure to support airbags which might be deployed from steering wheels or instrument panels of the golf carts, as in standard automobiles. The angle of the steering column, for example, is generally poor such that even if an airbag were situated in and deployed from a steering wheel during a crash, the impact of a driver with such an airbag would cause excessive rotation of the steering column, thereby substantially reducing the effectiveness of the deploying airbag. Additionally, the crash pulse from a frontal impact will be of extremely short duration making it very difficult to deploy airbags in time to protect the occupant during a frontal impact.
Seatbelts offer the best opportunity for protecting occupants of these vehicles. However, when used to transport golfers around golf courses, the requirement of buckling and unbuckling a seatbelt every time an occupant enters into and disembarks from the vehicle would be unacceptable. Thus, a system is needed which mandates the use of seatbelts while the vehicle is traveling at higher speeds and/or on higher speed limit roadways.
In this regard, U.S. Pat. No. 3,226,674, incorporated by reference herein, discloses a safety interlock system for automobiles which permits the operation of the vehicle at low speeds but requires the use of seatbelts at higher speeds.
Although seatbelts will provide a significant safety feature for golf carts, ATVs and similar vehicles, they are insufficient to protect occupants in all but minor accidents. The lack of structure in these vehicles exposes occupants to severe intrusion risks, plus standard seatbelts allow significant motion of the occupant particularly in side impacts. Thus, other protection mechanisms are necessary such as seatbelt-resident airbags and airbags which deploy from the seat structure. For seatbelt-resident airbags, a seatbelt switch interlock system is desirable. This prevents the airbags from deploying, except when they are engaged even if the seat is occupied.
A crash sensor system for assessing the need for airbag deployment could utilize a distributed sensor system in the crush zone of the vehicle as is common in automobile airbag systems. However, since the occupants are required to use seatbelts in this system, and, due to the short space between the front of the vehicle and the passenger compartment, distributed crash sensors will not provide a significant time advantage nor is this advantage needed since the occupants are wearing seatbelts. A single point passenger compartment sensor will satisfy the requirements of this system. One candidate for such a single point crash sensor is disclosed in U.S. patent application Ser. No. 14/069,760, cross-referenced above.
Although golf carts, ATVs and similar vehicles contain speedometers, such devices are easily disconnected either by accident or by intention. The GPS corrected IMU crash sensor of the ′760 patent application contains an inertial measurement unit which is capable of accurately determining the velocity of the vehicle independently of the vehicles speedometers. This device can thus be used to control a governor or other system that limits the vehicle speed, in particular, if the seatbelts are not engaged.
In addition to a speed requirement, it can be additionally required that when the vehicle operates on a known roadway, the seatbelts also are required to be worn. The GPS system contained in the GPS corrected IMU crash sensor of the ′760 patent application can also be used in conjunction with a map database to indicate the class of road on which the vehicle is traveling. In this case, the vehicle speed can be curtailed if the seatbelts are not engaged.